Succinyladenosine (SAdo) is one of the dephosphorylated enzyme substrate that accumulates in body fluids of patients with adenylosuccinate lyase (ADSL) deficiency, the other being 5-amino-4-imidazole-N-succinocarboxamide riboside (SAICAr). ADSL is an inherited metabolic disease characterized by various degrees of psychomotor retardation. (PMID 15902552 ). The severity of the clinical presentation correlates with a low S-Ado/SAICAr ratio in body fluids. (PMID: 15571235 ). Normally Succinyladenosine is not found in blood or CSF but may be detected in trace amounts in urine. (OMIM 103050 ).